CVE-2021-20795
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedCross-site request forgery (CSRF) vulnerability in the management screen of Cybozu Remote Service 3.1.8 to 3.1.9 allows a remote attacker to hijack the authentication of administrators and unintended operations may be performed via unspecified vectors.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · moderate confidenceCross-site request forgery (CSRF) vulnerability in the management screen of Cybozu Remote Service versions 3.1.8 to 3.1.9 allows remote attackers to execute unauthorized administrative actions by tricking authenticated administrators into triggering malicious requests.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data= 3.1.8= 3.1.9CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- Required
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Identify Cybozu Remote Service installationLocate and inspect the Cybozu Remote Service installation directory, or use system inventory tools to find the installed product. Check for files named 'version.txt', 'product.info', or check the Windows Registry (HKLM\SOFTWARE\Cybozu\RemoteService) for version information.Affected if The product is not installed or version cannot be determined, then the vulnerability does not apply.
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Confirm installed version matches affected rangeRead the installed version string from the method above and compare it exactly to 3.1.8 or 3.1.9.Affected if The installed version is exactly 3.1.8 or exactly 3.1.9, then the environment is affected.
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Verify management screen is accessibleConfirm that the Cybozu Remote Service Manager web interface or administrative console is accessible to users who could be targeted by CSRF attacks (e.g., check that the management port/URL is not blocked by network segmentation).Affected if The management screen is accessible and the version is 3.1.8 or 3.1.9, then the CSRF vulnerability is present and exploitable.
The environment is affected only if Cybozu Remote Service Manager version 3.1.8 or 3.1.9 is installed and the management interface is accessible.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
From vendor dataApply the vendor patch or upgrade to a fixed version; implement anti-CSRF tokens on all management screen endpoints and validate request origin headers.
- Consultation4.0 h
- Implementation12.0 h
- Testing6.0 h
- Review / QA3.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $7,040.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-20795 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2021-20795 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
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